docs: def min_distance_to_segment(seglons, seglats, lons, lats):
      """
      This function computes the shortest distance to a segment in a 2D reference
      system.
  
      :parameter seglons:
          A list or an array of floats specifying the longitude values of the two
          vertexes delimiting the segment.
      :parameter seglats:
          A list or an array of floats specifying the latitude values of the two
          vertexes delimiting the segment.
      :parameter lons:
          A list or a 1D array of floats specifying the longitude values of the
          points for which the calculation of the shortest distance is requested.
      :parameter lats:
          A list or a 1D array of floats specifying the latitude values of the
          points for which the calculation of the shortest distance is requested.
      :returns:
          An array of the same shape as lons which contains for each point
          defined by (lons, lats) the shortest distance to the segment.
          Distances are negative for those points that stay on the 'left side'
          of the segment direction and whose projection lies within the segment
          edges. For all other points, distance is positive.
      """
  
      # Check the size of the seglons, seglats arrays
      assert len(seglons) == len(seglats) == 2
  
      # Compute the azimuth of the segment
      seg_azim = azimuth(seglons[0], seglats[0], seglons[1], seglats[1])
  
      # Compute the azimuth of the direction obtained
      # connecting the first point defining the segment and each site
      azimuth1 = azimuth(seglons[0], seglats[0], lons, lats)
  
      # Compute the azimuth of the direction obtained
      # connecting the second point defining the segment and each site
      azimuth2 = azimuth(seglons[1], seglats[1], lons, lats)
  
      # Find the points inside the band defined by the two lines perpendicular
      # to the segment direction passing through the two vertexes of the segment.
      # For these points the closest distance is the distance from the great arc.
      idx_in = numpy.nonzero(
          (numpy.cos(numpy.radians(seg_azim-azimuth1)) >= 0.0) &
          (numpy.cos(numpy.radians(seg_azim-azimuth2)) <= 0.0))
  
      # Find the points outside the band defined by the two line perpendicular
      # to the segment direction passing through the two vertexes of the segment.
      # For these points the closest distance is the minimum of the distance from
      # the two point vertexes.
      idx_out = numpy.nonzero(
          (numpy.cos(numpy.radians(seg_azim-azimuth1)) < 0.0) |
          (numpy.cos(numpy.radians(seg_azim-azimuth2)) > 0.0))
  
      # Find the indexes of points 'on the left of the segment'
      idx_neg = numpy.nonzero(numpy.sin(numpy.radians(
          (azimuth1-seg_azim))) < 0.0)
  
      # Now let's compute the distances for the two cases.
      dists = numpy.zeros_like(lons)
      if len(idx_in[0]):
          dists[idx_in] = distance_to_arc(
              seglons[0], seglats[0], seg_azim, lons[idx_in], lats[idx_in])
      if len(idx_out[0]):
          dists[idx_out] = min_geodetic_distance(
              (seglons, seglats), (lons[idx_out], lats[idx_out]))
  
      # Finally we correct the sign of the distances in order to make sure that
      # the points on the right semispace defined using as a reference the
      # direction defined by the segment (i.e. the direction defined by going
      # from the first point to the second one) have a positive distance and
      # the others a negative one.
      dists = abs(dists)
      dists[idx_neg] = - dists[idx_neg]
  
      return dists